The invention relates to threaded pipe connections and the like. More particularly, the invention relates to applying a lubricating material, such as pipe dope, to the internal threads of a pipe.
In the oil and gas production industry, threaded pipe connections are often used. Special types of lubricant compositions are used for application between the male and female parts of these threaded tubular connections. The use of a pipe thread dope, or “pipe dope” as it has been called, may be required to provide a more stable joint. Pipe dope is a paste-like material that is applied to clean internal pipe threads just prior to joint assembly and provides three basic benefits to a threaded pipe joint. First, it lubricates the threads to ease assembly. Second, it acts as a sealant that enhances the gas-tightness or fluid-tightness of the resulting joint. And third, it hardens or cures to effectively cement and stabilize the joint.
The process of applying pipe dope has basically not changed since its original utilization. Pipe dope is commonly packaged in tins, or cans, of varying size, so one may purchase a quantity that is appropriate to the task at hand. The common method of applying pipe dope is to acquire a portion of the dope from the tin with the brush, and apply the dope to internal pipe threads by brushing. This method does not, however, assure a uniform application of the dope, either over the threads of one fitting or from joint to joint. Also, the amount of dope used is not regulated or controlled, so too much or too little dope may be used. Each of these situations may compromise the quality, durability, and reliability of the resulting threaded pipe joint. For example, too little pipe dope on the threads may result in increased friction in the threads during spinning, which may cause galling of the threaded surface. Conversely, too much pipe dope on the threads may result in pollution of the system (e.g. excess pipe dope may fall into the drillstring).
In conventional methods, the quality of a threaded pipe joint is highly dependent upon the skill or craftsmanship of the user in applying the pipe dope. Thus, an apparatus to provide a uniform application of an appropriate quantity of pipe dope will greatly benefit the quality of threaded pipe joints.